Reciprocating compressor having means for separating gaseous refrigerant from foam



May 3, 1949. D. F. SHEPHERD 2,469,086

RECIFROCATING COMPRESSOR HAVING MEANS FOR SEPARATING GASEOUS REFRIGERANTFROM FOAM Filed Dec. 6, 1946 2 Sheets-Sheet 1 FlG.l

INVENTOR.

y 3, 194% D. F. SHEPHERD 2,

RECIPROCATING COMPRESSOR HAVING MEANS FOR SEPARATING GASEOUS REFRIGERANTFROM FOAM Fil ed Dec. 6, 1946 2 She'ets-Sheet 2 FBG.2

IN VEN TOR.

Patented May 3, 1949 RECIPROCATING COMPRESSOR HAVING MEANS FORSEPARATING GASEOUS REFRIGERAN T FROM FOAM Daniel F. Shepherd, Syracuse,N. Y., assignor to Carrier Corporation, Syracuse, N. Y., a comration ofDelaware Application December 8. 1946, Serial No. 714,581

11 Claims. (Cl. 230-206) This invention relates to reciprocatincompressors and more particularly to a reciprocating compressor providedwith means for separating gaseous refrigerant from foam created in thecrankcase during start-up of the compressor.

Considerable difliculty is experienced by the foaming of oil in thecrankcase of a compressor during start-up. The preferred refrigerant,dichlorodifluoromethane, commonly known as F-12, is miscible with thelubricating oil in all proportions. Thus, oil in the crankcase of thecompressor normally contains a large amount of gaseous refrigerant. shutdown over night, for example, and is started the next day, the pressurein the crankcase is considerably greater than pressure in the suctionmanifold. Accordingly, upon start-up, the oil in the crankcase foams,and such foaming is encountered for perhaps the first ten minutes of theoperation. During this time the foam is drawn into the compressor and isdistributed throughout the refrigeration system. Occasionally,insufficient oil remains in the crankcase to lubricate satisfactorilyvarious elements of the compressor, with the result that damage orfaulty operation may occur.

The chief object of the present invention is to provide a device adaptedto separate gaseous refrigerant from foam thereby retaining the oil inthe foam in the crankcase upon start-up of a compressor.

from the following description.

This invention relates to a refrigerant compressor which includes acylinder, a crankcase, a crankshaft in said crankcase adapted to actuatethe cylinder piston, an oil sump in said crankcase, and means in thecrankcase for separating gaseous refrigerant from oil in foam created atstratup of the compressor; the separated gaseous refrigerant passin tothe suction manifold of the compressor and the separated oil returnin tothe sump. Preferably, such means comprises a fan disposed in thecrankcase adapted to separate When the compressor is by centrifugalaction the gaseous refrigerant from the oil in the foam; the centrifugalfan may be actuated by the crankshaft. After foaming has substantiallysubsided, the fan serves to draw oil collected in the suction manifoldinto the crankcase.

The attached drawing illustrates a preferred embodiment of my invention,in which:

Figure 1 is a diagrammatic view illustrating a. compressor provided withthe separating fan of the present invention; and

Figure 2 is a sectional view through the crankcase of the compressor.

Referring to the drawing, there is shown a reciprocating compressor 2including, preferably, a plurality of cylinders 3. Thecompressor 2 isactuated by any suitable power element; for example, a motor 2'connected to any suitable source of current. Each cylinder 3 contains apiston 4 connected by connecting rod 5 to the crankshaft 6 of thecompressor disposed in the crankcase I. An oil sump 8 is formed in thecrankcase I adapted to contain oil for lubricating various elements ofthe compressor. Ports 9 are provided connecting the crankcase l and thesuction manifold M of the compressor. Ports 5 are adapted to be closedby flapper valves 6 I, depending upon the difference in pressuresexisting in the suction manifold and the crankcase.

A fan 82 is disposed at any suitable position in crankcase 'i toseparate gaseous refrigerant from oil in foam created at start-up of thecompressor. Fan i2 may be actuated by crankshaft t and serves primarilyto break down foam created at start-up by centrifugal action and byelimination or removal of the gaseous refrigerant therefrom.

Fan it includes a ring or washer member it which may be secured by anysuitable means to the counterweight of the crankshaft or to thecrankshaft. Mounted on member 93 and preferably riveted thereto is animpeller member provided with a plurality of impellers IS. A shroud i'lincluding a ring i8 and a vertically extending member 69 having a flange20 at a right angle to the body of member i9 is disposed adjacentimpeller member 55. Flange 20 partially extends over adjacent impellersIS in order to reduce leakage. Shroud I1 is pinned in nonrotatingposition. An opening 2| extends through member I9 to the inlet 22 oflines 23 leading to the suction manifold III, as hereinafter described.

Considering the operation of the device, at start-up it will beappreciated that pressure in the crankcase I is considerably greaterthan asoaoso pressure in the suction manifold It of the coinpressor.

erant from the oil, to break the foam, passing the separated gaseousrefrigerant through opening 2|, inlet 22, and lines 23 to the suctionmanifold I0, while permitting the'separated oil to return to sump 8 incrankcase '1. Such action can-*- tinues until foaming has substantialiysubsided, thus preventing possibility of damage or injury to thecompressor due to the presence of insufflcient oil in the crankcase toeffect satisfactory lubrication. I

It will be appreciated this problem of foaming in the crankcase existsfor a short period of time only. After pressures in the crankcase and.the

suction manifold have been substantially equalized, the check valvesopen providing additional openings for equalization which in turnpermits fan I: to reverse the gas flow thereby drawing oil collected inthe suction manifold, as shown in Figure 2, into the crankcase. Fan 12thus serves in effect toeliminate the dangers created by foaming duringstart-up of the compressor and to assist in the return of .oil in therefrigeration system to the crankcase during the remaining period ofoperation of the compressor.

My invention provides a simple and inexpensive device to eliminate thedifficulties involved in foaming during start-up of a reciprocatingcgmpressor. While the device does not eliminate the formation of foam,it serves to break any foam created easily and readily, thus assuringthe maintenance of an adequate supply of oil in the crankcase forlubrication purposes to prevent damage or faulty operation due tofailure to lubricate satisfactorily various elements of the compressor.The device so provided may be disposed in any desired position in thecrankcase for ease of assembly and operation. 1

While I have described and illustrated a preferred embodiment of myinvention, it will be understood my invention is not limitedtheretosince it may be otherwise embodied within the scope of the followingclaims. 1 I claim: I

1. In apparatus of the character described, the combination of acompressor, a suction line connected to the compressor, an oil sumpserving as a source of lubricant for various elements of the compressor,and a separator fan for separating gaseous refrigerant from oil in foamcreated at start-up of the compressor, the separated gaseous refrigerantpassing to the suction line of the compressor and the separated oilpassing to the sump. 1 2. Apparatus according to claim 1 in which saidfan serves to withdraw oil collected in the created at start-up of thecompressor, the

separated gaseous refrigerant passing to the suction manifold of thecompressor and the separated oil returning to the sump.

4. A compressor according to claim 3 in which said separator fan isactuated by the crankshaft.

5. A compressor according to claim 3 in which said separator fan servesto withdraw oil trapped in the suction manifold andto return such oil tothe sump after the foam created at start-up of the compressor hassubstantially subsided.

6. In a compressor, the combination of a cylinder, a piston in saidcylinder, a crankcase, a crankshaft in said crankcase adapted to actuatethe cylinder piston, an oil sump in said crankcase. and a separator fanin said crankcase actuated by said crankshaft, said fan serving toseparate gaseous refrigerant from oil in foam created at start-up of thecompressor, a suction manifold connected to the cylinder, and a lineconnecting said fan with the suction manifold to forward the separatedgaseous refrigerant to the suction manifold, the separated oil beingreturned to the sump, said fan serving to drawbil trapped in the suctionmanifold into the crankcase after foam created at start-up of thecompressor has substantially subsided.

suction line and to return the oil to the sump after the foam created atstart-up of the com 7. In a compressor, the combination of a cylinder, apiston in said cylinder, a. crankcase, a crankshaft in said'crankcaseadapted to acuate the cylinder piston, an oil sump in saidcrankcase, a suction manifold connected to the cylinder, pressure insaid crankcase being greater at start-up of the compressor than thepressure in the suction manifold, a port connecting the suction manifoldand the crankcase, means for clos-' ing said port when pressure inSaidcrankcase reaches a predetermined oint greater than pressure in thesuctipn manifold, a fan mounted on said crankshaft and actuated thereby,a line con necting thg fan with the suction manifold, said fan servin tobreak up foam created at start-up of the compressor due to thedifference in pressure in the crankcase and the suction manifold and toforward the separated gaseous refrigerant through said line to thesuction manifold while permitting the separated oil to return to thesump, and after operation of the compressor has continued fora period oftime sufficient to equalize substantially the pressures in the crankcaseand the suction manifold, thereby permitting said means to open saidport, serving to draw oil collected in the suction manifold into thecrankcase.

8. .A compressor according to claim 7 in which the fan comprises a ringmember adapted to be attached to the crankshaft, an impeller memberattached to said ring member, and a shroud member having an vopeningtherein leading to said line, said fan servingto separate gaseous re-vfrigerant from oil in the foam by centrifugal action and to pass theseparated gaseous refrigerant through the shroud opening and said lineto the suction manifold, the separated oil returning to the sump. I

9. A device for substantially eliminating thedeleterious effects offoaming at start-up of a compressor including a suction manifold andacrankcase which comprises 7 a fan adapted to separategaseousrefrigerant in the foam by centrifugal action and to pass theseparated gaseous refrigerant to the suction of the compressor, said fanincluding a ring member, an impeller member attached to the ring memberand a shroud mem-" ber connected to the suction of the compressor, andmeans for actuating said fan upon startup of the compressor.

10. A device according to claim 9 in which the fan serves to withdrawtrapped oil from the suction manifold of the compressor after foaminghas substantially subsided due to substantial equalization of pressuresin the crankcase and the suction manifold.

11. A device for substantially eliminating the deleterious eflects offoaming at start-up of a compressor including a suction manifold, acrankcase and a crankshaft which comprises a fan disposed in thecrankcase of the compressor, said fan separating gaseous refrigerantfrom foam in the crankcase by centrifugal action, passing the separatedgaseous refrigerant to the suction manifold of the compressor andreturning separated oil to a; sump in the crankcase, said fan includinga ring member mounted on the crankshaft of the compressor and adapted torotate therewith, an impeller member attached to said ring member, ashroud member disposed adjacent.

the impeller member, and a line connecting the shroud member and thesuction manifold of the compressor.

DANIEL F. SHEPHERD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

